From: Thomas Gleixner <tglx@linutronix.de>
To: Fabio Estevam <festevam@gmail.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
Kalle Valo <kvalo@codeaurora.org>,
ath10k@lists.infradead.org, linux-mmc <linux-mmc@vger.kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>, Marek Vasut <marex@denx.de>,
qais.yousef@arm.com, Frederic Weisbecker <frederic@kernel.org>
Subject: Re: NOHZ tick-stop error with ath10k SDIO
Date: Sun, 05 Sep 2021 15:00:32 +0200 [thread overview]
Message-ID: <87y28b9nyn.ffs@tglx> (raw)
In-Reply-To: <CAOMZO5BnPEnF-HNM7vCzeUrRW7BsQ-hhm4fcVmO_QieKf6oJsw@mail.gmail.com>
Fabio,
On Sat, Sep 04 2021 at 18:10, Fabio Estevam wrote:
> On Fri, Sep 3, 2021 at 5:07 AM Thomas Gleixner <tglx@linutronix.de> wrote:
> I did as suggested and here is trace.txt:
> https://pastebin.com/VUfLRJ8a
Lacks a stack trace, but yes this one is the culprit:
kworker/u4:2-70 [000] d..1 87.940929: softirq_raise: vec=3 [action=NET_RX]
It has only interrupts and preemption disabled and it's in task
context. So if there is no interrupt raised and no local_bh_disable /
enable() pair invoked before the CPU goes idle nothing will handle the
softirq and the raised bit stays pending which makes the NOHZ idle code
complain.
> Also, while investigating this problem I saw a commit that fixed a
> similar issue:
> e63052a5dd3c ("mlx5e: add add missing BH locking around napi_schdule()").
>
> I then tried the same approach on the ath10k sdio driver:
>
> diff --git a/drivers/net/wireless/ath/ath10k/sdio.c
> b/drivers/net/wireless/ath/ath10k/sdio.c
> index b746052737e0..eb705214f3f0 100644
> --- a/drivers/net/wireless/ath/ath10k/sdio.c
> +++ b/drivers/net/wireless/ath/ath10k/sdio.c
> @@ -1363,8 +1363,11 @@ static void
> ath10k_rx_indication_async_work(struct work_struct *work)
> ep->ep_ops.ep_rx_complete(ar, skb);
> }
>
> - if (test_bit(ATH10K_FLAG_CORE_REGISTERED, &ar->dev_flags))
> + if (test_bit(ATH10K_FLAG_CORE_REGISTERED, &ar->dev_flags)) {
> + local_bh_disable();
> napi_schedule(&ar->napi);
> + local_bh_enable();
> + }
> }
>
> and no longer get the "NOHZ tick-stop error: Non-RCU local softirq work is
> pending, handler #08!!!" error messages after launching hostapd.
>
> Is this a proper fix?
Yes. This is correct. See above.
Thanks,
tglx
_______________________________________________
ath10k mailing list
ath10k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath10k
next prev parent reply other threads:[~2021-09-05 13:00 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-18 15:18 NOHZ tick-stop error with ath10k SDIO Fabio Estevam
2021-08-18 15:43 ` Paul E. McKenney
2021-08-18 16:29 ` Fabio Estevam
2021-08-18 17:02 ` Fabio Estevam
2021-08-18 17:56 ` Paul E. McKenney
2021-08-19 13:24 ` Fabio Estevam
2021-09-02 21:51 ` Thomas Gleixner
2021-09-02 22:09 ` Paul E. McKenney
2021-09-03 8:07 ` Thomas Gleixner
2021-09-04 21:10 ` Fabio Estevam
2021-09-05 13:00 ` Thomas Gleixner [this message]
2021-09-05 13:07 ` Fabio Estevam
2021-09-17 16:32 ` Qais Yousef
2021-09-17 17:09 ` Paul E. McKenney
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87y28b9nyn.ffs@tglx \
--to=tglx@linutronix.de \
--cc=ath10k@lists.infradead.org \
--cc=festevam@gmail.com \
--cc=frederic@kernel.org \
--cc=kvalo@codeaurora.org \
--cc=linux-mmc@vger.kernel.org \
--cc=marex@denx.de \
--cc=paulmck@kernel.org \
--cc=qais.yousef@arm.com \
--cc=ulf.hansson@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).